Hydraulically actuated synchronized transmission

Abstract

A transmission shift system comprising a synchronizing device for idler wheels, which can be actuated hydraulically and comprises at least one piston that can mesh with a selected idler wheel as the sliding sleeve. The piston can be displaced axially on a shaft via a hydraulic actuation and is non-rotatably connected with it, thus self-locking synchronization is provided.

1. A transmission shift system comprising a synchronizing device, for an idler wheel, which can be actuated hydraulically and comprises at least one sliding sleeve piston ( 1 ) that can mesh with a selected idler wheel ( 3 ), the piston ( 1 ) is non-rotatably connected with a shaft ( 9 ) and can be displaced axially on the shaft ( 9 ) by hydraulic actuation, a self-locking synchronization is provided by at least a first friction plate ( 2 ,  4 ) comprising a friction surface facing the idler wheel ( 3 ); and at least the first friction plate ( 2 ,  4 ) comprises at least one set of interior teeth ( 17 ,  17 ′) which is provided for connection with the shaft ( 9 ). 
   
   
     2. The transmission shift system according to  claim 1 , wherein the synchronizing device comprises a piston carrier ( 5 ) accommodating the piston ( 1 ), said piston carrier is non-rotatably connected to the shaft ( 9 ) and comprising a pressure oil feed line ( 10 ) so that a piston chamber, between the piston ( 1 ) and the piston carrier ( 5 ), is provided which can be supplied with pressure for hydraulically actuating the piston ( 1 ). 
   
   
     3. The transmission shift system according to  claim 1 , wherein the piston ( 1 ) is a step-shaped annular flange which, on an outside step, comprises first set of interior teeth ( 12 ) for connecting with the idler wheel ( 3 ) and, on an inside step, comprises second set of interior teeth ( 13 ) for connecting with the shaft ( 9 ). 
   
   
     4. The transmission shift system according to  claim 3 , wherein at least ends of the first set of interior teeth ( 12 ) of the piston ( 1 ) facing the idler wheel ( 3 ) are chamfered. 
   
   
     5. The transmission shift system according to  claim 1 , wherein the idler wheel ( 3 ) comprises a running gear ( 15 ) for positive connection with an additional torque-transmitting element and a set of coupling teeth ( 16 ) for positive connection with the piston ( 1 ) and the idler wheel ( 3 ) is rotatably seated on the shaft ( 9 ). 
   
   
     6. The transmission shift system according to  claim 1 , wherein in an axial direction between the piston ( 1 ) and the idler wheel ( 3 ), the first friction plate ( 2 ) with the set of interior teeth ( 17 ) and a set of exterior teeth ( 18 ) is provided, and the set of exterior teeth ( 18 ) is chamfered at least on an end facing the piston ( 1 ). 
   
   
     7. The transmission shift system according to  claim 1 , wherein the first friction plate ( 2 ), during a synchronizing phase, is provided as a locking element resulting in a self-locking synchronizing device. 
   
   
     8. The transmission shift system according to  claim 1 , wherein teeth of a first set of interior teeth ( 12 ) of the piston ( 1 ) can be guided through respective intermediate spaces between teeth of a first set of exterior teeth ( 18 ) of the first friction plate ( 2 ) for shifting purposes so that the piston ( 1 ), connected to the shaft ( 9 ), can be positively connected to the idler wheel ( 3 ). 
   
   
     9. The transmission shift system according to  claim 1 , wherein a second friction plate ( 4 ) is arranged on a side of the idler wheel ( 3 ) facing away from the piston ( 1 ). 
   
   
     10. The transmission shift system according to  claim 9 , wherein a third friction plate ( 11 ) and a fourth friction plate ( 19 ) are provided, and the fourth friction plate ( 19 ) is arranged between the second friction plate ( 4 ) and the third friction plate ( 11 ). 
   
   
     11. The transmission shift system according to  claim 1 , wherein at least one return spring ( 6 ) is provided for returning the piston ( 1 ) to an unshifted position. 
   
   
     12. The transmission shift system according to  claim 11 , wherein a plurality of return springs ( 6 ) are provided, and the plurality of return springs ( 6 ) are evenly distributed about a circumference of the piston ( 1 ). 
   
   
     13. The transmission shift system according to  claim 1 , wherein at least one sealing element ( 21 ,  21 ′) is provided between a piston carrier ( 5 ) and the piston ( 1 ) to seal a piston chamber. 
   
   
     14. The transmission shift system according to  claim 7 , wherein interior teeth of the first friction plate ( 2 ) have play, in relation to the shaft ( 9 ), that is as large as an intermediate space between two adjoining teeth of a first set of interior teeth ( 12 ) of the piston.